Fix groups validation error

ckanext/odsh/validation.py

@@ -12,6 +12,9 @@ from ckan.lib.navl.dictization_functions import Missing
 
 from pylons import config
 
+import logging
+log = logging.getLogger(__name__)
+
 def _extract_value(data, field):
     key = None
     for k in data.keys():
@@ -24,6 +27,9 @@ def _extract_value(data, field):
 
 def validate_extra_groups(data, requireAtLeastOne, errors):
     value = _extract_value(data, 'groups')
+    if value != None:
+        # 'value != None' means the extra key 'groups' was found,
+        # so the dataset came from manual editing via the web-frontend.        
         if not value:
             if requireAtLeastOne:
                 errors['groups']= 'at least one group needed'
@@ -42,7 +48,10 @@ def validate_extra_groups(data, requireAtLeastOne, errors):
 
         for num, group in zip(range(len(groups)), groups):
             data[('groups', num, 'id')] = group
-    
+    else: # no extra-field 'groups'
+        # dataset might come from a harvest process
+        if not data[('groups', 0, 'id')]:
+            errors['groups']= 'at least one group needed'
 
 def validate_extras(key, data, errors, context):
     extra_errors = {}